interface Fly
	{
	void refill();
	}
interface Flyable extends Fly
	{
	void start();
	void fly();
	void stop();
	}
class Aeroplane implements Flyable
	{
	public void start()
		{
		System.out.println("Aeroplane starting");
		}
	public void fly()
		{
		System.out.println("Aeroplane is flying");
		}
	public void stop()
		{
		System.out.println("Aeroplane has stopped flying");
		}
	public void refill()
		{
		System.out.println("50 Litres refilled");
		}
	}
class Helicopter implements Flyable
	{
	public void start()
		{
		System.out.println("Helicopter starting");
		}
	public void fly()
		{
		System.out.println("Helicopter  is flying");
		}
	public void stop()
		{
		System.out.println("Helicopter  has stopped flying");
		}
	public void refill()
		{
		System.out.println("50 Litres refilled");
		}
	}
class Jet implements Flyable
	{
	public void start()
		{
		System.out.println("Jet starting");
		}
	public void fly()
		{
		System.out.println("Jet is flying");
		}
	public void stop()
		{
		System.out.println("Jet has stopped flying");
		}
	public void refill()
		{
		System.out.println("50 Litres refilled");
		}
	}

class InterfaceDemo
	{
	public static void main(String[] arga)
		{
		Flyable f1=new Aeroplane();
		f1.start();
		f1.fly();
		f1.stop();
		f1.refill();
		}
	} 
	